Lubricant composition for gear oil

ABSTRACT

The present invention relates to a lubricant composition, and more particularly to a lubricant composition, which includes an ethylene-alphaolefin oligomer and an alkylated phosphonium compound, thus realizing energy reduction and an increased endurance life, and which is thus suitable for use in gear oil. The lubricant composition of the present invention includes a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Korean Patent Application No. 10-2019-0023683, filed on Feb. 28, 2019 with the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION 1. Technical Field

The present invention relates to a lubricant composition, and more particularly to a lubricant composition, which includes an ethylene-alphaolefin oligomer and an alkylated phosphonium compound, thus realizing energy reduction and an increased endurance life, and which is thus suitable for use in gear oil.

2. Description of the Related Art

Recently, as environmental problems such as global warming, destruction of the ozone layer, etc. have come to the fore, environmental regulations have become strict. Hence, reduction of carbon dioxide emissions is receiving a great deal of attention. In order to reduce carbon dioxide emissions, it is urgent to decrease energy consumption in vehicles, construction machinery, agricultural machinery and the like, that is, to increase fuel economy, and thus there is a strong demand for measures capable of contributing to energy reduction in an engine, a transmission, a final reducer, a compressor, a hydraulic device and the like. Accordingly, lubricants used in such devices are required to have the ability to decrease stirring resistance or friction resistance compared to conventional cases.

A lubricant is an oily material used to reduce the generation of frictional force on the friction surface of a machine or to dissipate frictional heat generated from the friction surface. The lubricant is manufactured by adding additives to base oil, and is largely classified into a mineral-oil-based lubricant (petroleum-based lubricant) and a synthetic lubricant depending on the type of base oil, the synthetic lubricant being classified into a polyalphaolefin-based lubricant and an ester-based lubricant.

As means for improving fuel economy in gears of transmissions and reducers, decreasing the viscosity of a lubricant is generally used. For example, among transmissions, an automatic transmission or a continuously variable transmission for vehicles has a torque converter, a wet clutch, a gear bearing mechanism, an oil pump, a hydraulic control mechanism, etc., and a manual transmission or a reducer has a gear bearing mechanism, and thus when the viscosity of lubricant used therefor is further decreased, stirring resistance and friction resistance of the torque converter, the wet clutch, the gear bearing mechanism, and the oil pump are decreased, thereby increasing power transmission efficiency, ultimately making it possible to improve the fuel economy of vehicles.

However, when the viscosity of conventional lubricants is lowered, fitting performance is greatly decreased due to the deterioration of friction performance, and sticking or the like occurs, thus causing defects in the transmission or the like. Particularly, in the case of low viscosity, a viscosity modifier is sheared during the use thereof, and thus the viscosity is lowered, so that the wear resistance of the gear is damaged and fitting performance is easily deteriorated. Furthermore, even when a sulfur/phosphorus extreme pressure agent is added to increase the extreme pressure performance of low-viscosity oil, fitting performance and endurance life are remarkably decreased, making it difficult to realize long-term use thereof.

Therefore, the present inventors have developed a lubricant composition for gear oil, which is capable of reducing the mechanical wear of gear parts and energy consumption and also of exhibiting superior thermal stability and oxidation stability, and may thus be industrially used for a long period of time.

CITATION LIST Patent Literature

(Patent Document 0001) Korean Patent No. 10-1420890

(Patent Document 0002) Korean Patent No. 10-1347964

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the problems encountered in the related art, and an objective of the present invention is to provide a lubricant composition, in which a functional additive for friction reduction and an ethylene-alphaolefin liquid random copolymer are mixed, thereby exhibiting superior friction characteristics, thermal stability and oxidation stability.

Another objective of the present invention is to provide a lubricant composition for gear oil, which is able to reduce the mechanical wear of gear parts and energy consumption when applied to gears of transmissions and reducers, and may be used for a long period of time due to low changes in the physical properties of gear oil.

In order to accomplish the above objectives, the present invention provides a lubricant composition, comprising a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.

The base oil may be at least one selected from the group consisting of mineral oil, polyalphaolefin (PAO) and ester.

The liquid olefin copolymer may be prepared by copolymerizing ethylene and alphaolefin in the presence of a single-site catalyst system, and the single-site catalyst system preferably includes a metallocene catalyst, an organometallic compound and an ionic compound.

The liquid olefin copolymer may have a coefficient of thermal expansion of 3.0 to 4.0.

In the lubricant composition of the present invention, the liquid olefin copolymer may be included in an amount of 0.1 to 30 wt %, and preferably 0.5 to 25 wt %. The alkylated phosphonium compound may be included in an amount of 0.1 to 5.0 wt %, and preferably 0.3 to 4.0 wt %.

The lubricant composition may have an SRV friction coefficient of 0.2 to 0.3 and a traction coefficient of 0.15 to 0.3. Moreover, the lubricant composition may have a pinion torque loss rate due to friction of less than 1% in an FZG gear efficiency test.

According to the present invention, a lubricant composition includes an alkylated phosphonium compound as a friction-reducing agent, in addition to an existing sulfur/phosphorus extreme pressure agent, thereby maximizing friction performance to thus reduce the mechanical wear of gear parts and energy consumption when applied to gears of transmissions and reducers, ultimately maximizing energy-saving effects.

Also, according to the present invention, the lubricant composition includes, as a viscosity modifier, an olefin copolymer prepared in the presence of a metallocene compound catalyst, and can thus exhibit a high viscosity index and superior low-temperature stability.

Therefore, the present invention can provide a lubricant composition for gear oil, which enables long-term use due to low changes in the physical properties of gear oil.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, a detailed description will be given of the present invention.

The present invention relates to a lubricant composition, which has superior oxidation stability and friction characteristics and is thus suitable for use in gear oil. Hence, the lubricant composition of the present invention includes a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.

Here, the base oil varies from the aspects of viscosity, heat resistance, oxidation stability and the like depending on the manufacturing method or refining method, but is generally classified into mineral oil and synthetic oil. The API (American Petroleum Institute) classifies base oil into five types, namely Group I, II, III, IV and V. These types, based on API ranges, are defined in API Publication 1509, 15^(th) Edition, Appendix E, April 2002, and are shown in Table 1 below.

TABLE 1 Saturated hydrocarbon Sulfur Viscosity (%) (%) index Group I <90 >0.03 80 ≤ VI < 120 Group II ≥90 ≤0.03 80 ≤ VI < 120 Group III ≥90 ≤0.03 VI ≥ 120 Group IV PAO (Poly Alpha Olefin) Group V Ester & Others

In the lubricant composition of the present invention, the base oil may be at least one selected from the group consisting of mineral oil, polyalphaolefin (PAO) and ester, and may be any type among Groups I to V based on the API ranges.

More specifically, mineral oil belongs to Groups I to III based on the API ranges, and mineral oil may include oil resulting from subjecting a lubricant distillate fraction, obtained through atmospheric distillation and/or vacuum distillation of crude oil, to at least one refining process of solvent deasphalting, solvent extraction, hydrogenolysis, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid cleaning, and white clay treatment; wax isomerized mineral oil; or a gas-to-liquid (GLT) oil obtained via the Fischer-Tropsch process.

The synthetic oil belongs to Group IV or V based on the API ranges, and polyalphaolefin belonging to Group IV may be obtained through oligomerization of a higher alphaolefin using an acid catalyst, as disclosed in U.S. Pat. Nos. 3,780,128, 4,032,591, Japanese Patent Application Publication No. Hei. 1-163136, and the like, but the present invention is not limited thereto.

Examples of the synthetic oil belonging to Group V include alkyl benzenes, alkyl naphthalenes, isobutene oligomers or hydrides thereof, paraffins, polyoxy alkylene glycol, dialkyl diphenyl ether, polyphenyl ether, ester, and the like.

Here, the alkyl benzenes and alkyl naphthalenes are usually dialkylbenzene or dialkylnaphthalene having an alkyl chain length of 6 to 14 carbon atoms, and the alkyl benzenes or alkyl naphthalenes are prepared through Friedel-Crafts alkylation of benzene or naphthalene with olefin. The alkylated olefin used in the preparation of alkyl benzenes or alkyl naphthalenes may be linear or branched olefins or combinations thereof.

Also, examples of the ester include, but are not limited to, ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, tridecyl pelargonate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, trimethylolpropane caprylate, trimethylolpropane pelargonate, trimethylolpropane triheptanoate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, pentaerythritol tetraheptanoate, and the like.

In the lubricant composition of the present invention, the liquid olefin copolymer is prepared by copolymerizing ethylene and alphaolefin monomers in the presence of a single-site catalyst system in order to uniformly distribute alphaolefin units in the copolymer chain. Preferably, the liquid olefin copolymer is prepared by reacting ethylene and alphaolefin monomers in the presence of a single-site catalyst system including a crosslinked metallocene compound, an organometallic compound, and an ionic compound for forming an ion pair through reaction with the crosslinked metallocene compound.

Here, the metallocene compound included in the single-site catalyst system may be at least one selected from the group consisting of Chemical Formulas 1 to 6 below.

In Chemical Formulas 1 to 4,

-   -   M is a transition metal selected from the group consisting of         titanium, zirconium, and hafnium,     -   B is absent or is a linking group including a C1-C20 alkylene         group, a C6-C20 arylene group, C1-C20 dialkyl silicon, C1-C20         dialkyl germanium, a C1-C20 alkylphosphine group or a C1-C20         alkylamine group,     -   X₁ and X₂, which are the same as or different from each other,         are each independently a halogen atom, a C1-C20 alkyl group, a         C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C20 aryl         group, a C7-C40 alkylaryl group, a C7-C40 arylalkyl group, a         C1-C20 alkylamido group, a C6-C20 arylamido group, a C1-C20         alkylidene group or a C1-C20 alkoxy group, and     -   R₁ to R₁₀, which are the same as or different from each other,         are each independently hydrogen, a C1-C20 alkyl group, a C2-C20         alkenyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, a         C7-C20 arylalkyl group, a C5-C60 cycloalkyl group, a C4-C20         heterocyclic group, a C1-C20 alkynyl group, a         C6-C20-aryl-containing hetero group or a silyl group.

In Chemical Formulas 5 and 6,

-   -   M is a transition metal selected from the group consisting of         titanium, zirconium, and hafnium,     -   B is absent or is a linking group including a C1-C20 alkylene         group, a C6-C20 arylene group, a C1-C20 dialkyl silicon, a         C1-C20 dialkyl germanium, a C1-C20 alkylphosphine group or a         C1-C20 alkylamine group,     -   X₁ and X₂, which are the same as or different from each other,         are each independently a halogen atom, a C1-C20 alkyl group, a         C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C20 aryl         group, a C7-C40 alkylaryl group, a C7-C40 arylalkyl group, a         C1-C20 alkylamido group, a C6-C20 arylamido group, a C1-C20         alkylidene group or a C1-C20 alkoxy group, and     -   R₁ to R₁₀, which are the same as or different from each other,         are each independently hydrogen, a C1-C20 alkyl group, a C2-C20         alkenyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, a         C7-C20 arylalkyl group, a C5-C60 cycloalkyl group, a C4-C20         heterocyclic group, a C1-C20 alkynyl group, a         C6-C20-aryl-containing hetero group or a silyl group.

Furthermore, all of R₁₁, R₁₃ and R₁₄ are hydrogen, and each of R₁₂ radicals, which are the same as or different from each other, may independently be hydrogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, a C7-C20 arylalkyl group, a C5-C60 cycloalkyl group, a C4-C20 heterocyclic group, a C1-C20 alkynyl group, a C6-C20-aryl-containing hetero group or a silyl group.

Also, the metallocene compound of Chemical Formulas 2 to 6 may include a compound substituted through a hydroaddition reaction, and a preferred example thereof includes dimethylsilyl bis(tetrahydroindenyl) zirconium dichloride.

The organometallic compound included in the single-site catalyst system may be at least one selected from the group consisting of an organoaluminum compound, an organomagnesium compound, an organozinc compound and an organolithium compound, and is preferably an organoaluminum compound. The organoaluminum compound may be at least one selected from the group consisting of, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, dimethylisobutylaluminum, dimethylethylaluminum, diethylchloroaluminum, triisopropylaluminum, triisobutylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, methylaluminoxane, ethylaluminoxane, isobutylaluminoxane and butylaluminoxane, and is preferably triisobutylaluminum.

The ionic compound included in the single-site catalyst system may be at least one selected from the group consisting of organoboron compounds such as dimethylanilinium tetrakis(perfluorophenyl)borate, triphenylcarbenium tetrakis(perfluorophenyl)borate, and the like.

The component ratio of the single-site catalyst system may be determined in consideration of catalytic activity, and the molar ratio of metallocene catalyst:ionic compound:organometallic compound is preferably adjusted in the range of 1:1:5 to 1:10:1000 in order to ensure desired catalytic activity.

Furthermore, the components of the single-site catalyst system may be added at the same time or in any sequence to an appropriate solvent and may thus function as an active catalyst system. Here, the solvent may include, but is not limited to, a hydrocarbon solvent such as pentane, hexane, heptane, etc., or an aromatic solvent such as benzene, toluene, xylene, etc., and any solvent usable in the preparation may be used.

Also, the alphaolefin monomer used in the preparation of the liquid olefin copolymer includes a C2-C20 aliphatic olefin, and may specifically be at least one selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene and 1-tetradecene, and may include isomeric forms, but the present invention is not limited thereto. In the copolymerization, the monomer content is 1 to 95 mol %, preferably 5 to 90 mol %.

The liquid olefin copolymer required in the present invention has a coefficient of thermal expansion of 3.0 to 4.0 and a bromine number of 0.1 or less.

The liquid olefin copolymer may be included in an amount of 0.1 to 30 wt %, and preferably 0.5 to 25 wt %, based on 100 wt % of the lubricant composition. If the amount of the liquid olefin copolymer is less than 0.1 wt % based on 100 wt % of the lubricant composition, low-temperature stability may deteriorate. On the other hand, if the amount thereof exceeds 30 wt %, sufficient viscosity cannot be realized, and thus application of the resulting composition to gear oil becomes difficult, which is undesirable.

The alkylated phosphonium compound, serving as a friction-reducing agent, may be at least one selected from the group consisting of tetraoctylated phosphonium bisethylhexyl phosphate, tributyltetradecylphosphonium bis(2-ethylhexyl)phosphate, tetraethylphosphonium bis(2-ethylhexyl)phosphate and tributylphosphonium bis(2-ethylhexly)phosphate. When the alkylated phosphonium compound is included in the lubricant composition, it may exhibit synergistic effects with an existing wear-resistant agent and friction reduction effects, and additionally, energy-saving effects may be achieved through friction reduction.

The alkylated phosphonium compound may be included in an amount of 0.1 to 5.0 wt %, and preferably 0.3 to 4.0 wt %, based on 100 wt % of the lubricant composition. If the amount of the alkylated phosphonium compound is less than 0.1 wt % based on 100 wt % of the lubricant composition, the friction reduction effect is insignificant. On the other hand, if the amount thereof exceeds 5.0 wt %, the additional reduction effect is insignificant despite the excessive addition thereof, which is undesirable.

The lubricant composition of the present invention may further include an additive selected from the group consisting of an antioxidant, a metal cleaner, an anticorrosive agent, a foam inhibitor, a pour-point depressant, a viscosity modifier, a wear-resistant agent and combinations thereof.

The antioxidant may be included in an amount of 0.01 to 5.0 wt % based on 100 wt % of the lubricant composition, and is preferably used in the form of a mixture of a phenolic antioxidant and an aminic antioxidant, more preferably a mixture of 0.01 to 3.0 wt % of the phenolic antioxidant and 0.01 to 3.0 wt % of the aminic antioxidant.

The phenolic antioxidant may be any one selected from the group consisting of 2,6-dibutylphenol, hindered bisphenol, high-molecular-weight hindered phenol, and hindered phenol with thioether.

The aminic antioxidant may be any one selected from the group consisting of diphenylamine, alkylated diphenylamine and naphthylamine, and preferably, the alkylated diphenylamine is dioctyldiphenylamine, octylated diphenylamine, or butylated diphenylamine.

The metal cleaner may be at least one selected from the group consisting of metallic phenate, metallic sulfonate, and metallic salicylate, and preferably, the metal cleaner is included in an amount of 0.1 to 10.0 wt % based on 100 wt % of the lubricant composition.

The anticorrosive agent may be a benzotriazole derivative, and is preferably any one selected from the group consisting of benzotriazole, 2-methylbenzotriazole, 2-phenylbenzotriazole, 2-ethylbenzotriazole and 2-propylbenzotriazole. The anticorrosive agent may be included in an amount of 0 to 4.0 wt % based on 100 wt % of the lubricant composition.

The foam inhibitor may be polyoxyalkylene polyol, and preferably, the foam inhibitor is included in an amount of 0 to 4.0 wt % based on 100 wt % of the lubricant composition.

The pour-point depressant may be poly(methyl methacrylate), and preferably, the pour-point depressant is included in an amount of 0.01 to 5.0 wt % based on 100 wt % of the lubricant composition.

The viscosity modifier may be polyisobutylene or polymethacrylate, and preferably, the viscosity modifier is included in an amount of 0 to 15 wt % based on 100 wt % of the lubricant composition.

The wear-resistant agent may be at least one selected from the group consisting of organic borates, organic phosphites, organic sulfur-containing compounds, zinc dialkyl dithiophosphate, zinc diaryl dithiophosphate and phosphosulfurized hydrocarbon, and preferably, the wear-resistant agent is included in an amount of 0.01 to 3.0 wt %.

The lubricant composition of the present invention has an SRV friction coefficient of 0.2 to 0.3 and a traction coefficient of 0.15 to 0.3. Also, the lubricant composition of the present invention has a pinion torque loss rate due to friction of less than 1%, as measured through an FZG gear efficiency test as a gear oil rig test.

A better understanding of the present invention through the following examples. However, the present invention is not limited to these examples, but may be embodied in other forms. These examples are provided to thoroughly explain the invention and to sufficiently transfer the spirit of the present invention to those skilled in the art.

1. Preparation of Additive Composition

An additive composition for use in the lubricant composition of the present invention was prepared as shown in Table 2 below.

TABLE 2 Composition Composition Additive composition A B Antioxidant 2,6-dibutylphenol 1 1.5 Diphenylamine 0.8 1 Metal cleaner Metallic phenate 0.2 0.6 Anticorrosive Benzotriazole 0.3 1.0 agent Foam inhibitor Polyoxyalkylene polyol 0.01 0.02 Pour-point Polymethylmethacrylate 0.2 0.5 depressant Viscosity Polyisobutylene 1.0 modifier Wear-resistant Zinc diaryl 0.2 1.1 agent dithiophosphate

2. Liquid Olefin Copolymer

A liquid olefin copolymer was prepared using an oligomerization method through a catalytic reaction process. Depending on the reaction time and conditions, which follow, liquid olefin copolymers having different molecular weights were prepared, and the properties thereof are shown in Table 3 below.

The reaction time and conditions were increased by 4 hr each from 20 hr. Here, the amounts of hydrogen and comonomer C3, which were added thereto, were increased by 10% each, and polymerization was performed under individual conditions, and the resulting polymers were classified depending on the molecular weight thereof.

TABLE 3 Main properties Alphaolefin Evaporation Thickening Power CoE of copolymer Loss (%) (10 wt % in 150N) Thermal Expansion Copolymer I 1.28 6 3.00 to 3.20 Copolymer II 0.54 7 3.20 to 3.40 Copolymer III 0.10 8 3.40 to 3.50 Copolymer IV 0.001 10 3.50 to 3.60 Copolymer V 0.0001 12 3.60 to 3.70 Copolymer VI 0.00001 14 3.70 to 3.80

3. Preparation of Lubricant Composition for Gear Oil

A lubricant composition was prepared by mixing a base oil, the liquid olefin copolymer, an alkylated phosphonium compound, and the additive prepared above, as shown in Tables 4 and 5 below. Here, the base oil was polyalphaolefin (PAO 4 cSt, available from Chevron Philips) having kinematic viscosity of 4 cSt at 100° C., and the alkylated phosphonium compound was tetraoctylated phosphonium bisethylhexyl phosphate.

Preparation Examples 1 to 72 and Comparative Examples 1 to 9. Lubricant Composition for Gear Oil Including Additive A

TABLE 4 Base Alphaolefin Alkylated phosphonium Additive Composition oil copolymer compound A Preparation 97.14 Copolymer I 0.1 2.71 Example 1 0.05 Preparation 96.74 Copolymer I 0.5 2.71 Example 2 0.05 Preparation 96.24 Copolymer I 1.0 2.71 Example 3 0.05 Preparation 94.24 Copolymer I 3.0 2.71 Example 4 0.05 Preparation 92.24 Copolymer I 5.0 2.71 Example 5 0.05 Preparation 95.79 Copolymer I 1.0 2.71 Example 6 0.5 Preparation 93.79 Copolymer I 3.0 2.71 Example 7 0.5 Preparation 91.79 Copolymer I 5 0.5 2.71 Example 8 Preparation 89.29 Copolymer I 5 3.0 2.71 Example 9 Preparation 87.29 Copolymer I 5 5.0 2.71 Example 10 Preparation 86.79 Copolymer I 10 0.5 2.71 Example 11 Preparation 86.29 Copolymer I 10 1.0 2.71 Example 12 Preparation 82.29 Copolymer I 10 5.0 2.71 Example 13 Preparation 76.79 Copolymer I 20 0.5 2.71 Example 14 Preparation 72.29 Copolymer I 20 5.0 2.71 Example 15 Preparation 67.19 Copolymer I 30 0.1 2.71 Example 16 Preparation 62.29 Copolymer I 30 5.0 2.71 Example 17 Preparation 61.79 Copolymer I 35 0.5 2.71 Example 18 Preparation 61.29 Copolymer I 35 1.0 2.71 Example 19 Preparation 59.29 Copolymer I 35 3.0 2.71 Example 20 Preparation 57.29 Copolymer I 35 5.0 2.71 Example 21 Preparation 52.29 Copolymer I 35 10.0 2.71 Example 22 Preparation 97.14 Copolymer II 0.1 2.71 Example 23 0.05 Preparation 96.74 Copolymer II 0.5 2.71 Example 24 0.05 Preparation 96.24 Copolymer II 1.0 2.71 Example 25 0.05 Preparation 94.24 Copolymer II 3.0 2.71 Example 26 0.05 Preparation 92.24 Copolymer II 5.0 2.71 Example 27 0.05 Preparation 95.79 Copolymer II 1.0 2.71 Example 28 0.5 Preparation 93.79 Copolymer II 3.0 2.71 Example 29 0.5 Preparation 91.79 Copolymer II 5 0.5 2.71 Example 30 Preparation 91.29 Copolymer II 5 1.0 2.71 Example 31 Preparation 87.29 Copolymer II 5 5.0 2.71 Example 32 Preparation 87.19 Copolymer II 0.1 2.71 Example 33 10 Preparation 86.29 Copolymer II 1.0 2.71 Example 34 10 Preparation 84.29 Copolymer II 3.0 2.71 Example 35 10 Preparation 82.29 Copolymer II 5.0 2.71 Example 36 10 Preparation 77.19 Copolymer II 0.1 2.71 Example 37 20 Preparation 74.29 Copolymer II 3.0 2.71 Example 38 20 Preparation 72.29 Copolymer II 5.0 2.71 Example 39 20 Preparation 67.19 Copolymer II 0.1 2.71 Example 40 30 Preparation 97.14 Copolymer III 0.1 2.71 Example 41 0.05 Preparation 96.74 Copolymer III 0.5 2.71 Example 42 0.05 Preparation 96.24 Copolymer III 1.0 2.71 Example 43 0.05 Preparation 94.24 Copolymer III 3.0 2.71 Example 44 0.05 Preparation 91.79 Copolymer III 0.5 2.71 Example 45 5 Preparation 87.29 Copolymer III 5.0 2.71 Example 46 5 Preparation 86.79 Copolymer III 0.5 2.71 Example 47 10 Preparation 82.29 Copolymer III 5.0 2.71 Example 48 10 Preparation 76.79 Copolymer III 0.5 2.71 Example 49 20 Preparation 76.29 Copolymer III 1.0 2.71 Example 50 20 Preparation 72.29 Copolymer III 5.0 2.71 Example 51 20 Preparation 92.19 Copolymer IV 5 0.1 2.71 Example 52 Preparation 89.29 Copolymer IV 5 3.0 2.71 Example 53 Preparation 87.29 Copolymer IV 5 5.0 2.71 Example 54 Preparation 82.29 Copolymer IV 5 10.0 2.71 Example 55 Preparation 86.79 Copolymer IV 0.5 2.71 Example 56 10 Preparation 74.29 Copolymer IV 3.0 2.71 Example 57 20 Preparation 76.79 Copolymer IV 0.5 2.71 Example 58 20 Preparation 91.79 Copolymer V 5 0.5 2.71 Example 59 Preparation 86.79 Copolymer V 10 0.5 2.71 Example 60 Preparation 82.29 Copolymer V 10 5.0 2.71 Example 61 Preparation 77.19 Copolymer V 20 0.1 2.71 Example 62 Preparation 76.79 Copolymer V 20 0.5 2.71 Example 63 Preparation 72.29 Copolymer V 20 5.0 2.71 Example 64 Preparation 67.19 Copolymer V 30 0.1 2.71 Example 65 Preparation 66.79 Copolymer V 30 0.5 2.71 Example 66 Preparation 97.14 Copolymer VI 0.1 2.71 Example 67 0.05 Preparation 96.74 Copolymer VI 0.5 2.71 Example 68 0.05 Preparation 96.24 Copolymer VI 1.0 2.71 Example 69 0.05 Preparation 91.79 Copolymer VI 5 0.5 2.71 Example 70 Preparation 86.79 Copolymer VI 0.5 2.71 Example 71 10 Preparation 76.79 Copolymer VI 0.5 2.71 Example 72 20 Comparative 97.24 Copolymer I — 2.71 Example 1 0.05 Comparative 97.24 Copolymer II — 2.71 Example 2 0.05 Comparative 87.29 Copolymer II — 2.71 Example 3 10 Comparative 77.29 Copolymer II — 2.71 Example 4 20 Comparative 67.29 Copolymer II — 2.71 Example 5 30 Comparative 92.29 Copolymer IV 5 — 2.71 Example 6 Comparative 67.29 Copolymer V 30 — 2.71 Example 7 Comparative 62.29 Copolymer V 35 — 2.71 Example 8 Comparative 97.24 Copolymer VI — 2.71 Example 9 0.05

Preparation Examples 73 to 148 and Comparative Examples to 16. Lubricant Composition for Gear Oil Including Additive B

TABLE 5 Base Alphaolefin Alkylated phosphonium Additive Composition oil copolymer compound B Preparation 92.28 Copolymer I 0.5 6.72 Example 73 0.5 Preparation 91.78 Copolymer I 1.0 6.72 Example 74 0.5 Preparation 87.78 Copolymer I 5 0.5 6.72 Example 75 Preparation 87.28 Copolymer I 5 1.0 6.72 Example 76 Preparation 82.28 Copolymer I 1.0 6.72 Example 77 10 Preparation 80.28 Copolymer I 3.0 6.72 Example 78 10 Preparation 72.78 Copolymer I 0.5 6.72 Example 79 20 Preparation 72.28 Copolymer I 1.0 6.72 Example 80 20 Preparation 91.78 Copolymer II 1.0 6.72 Example 81 0.5 Preparation 89.78 Copolymer II 3.0 6.72 Example 82 0.5 Preparation 87.78 Copolymer II 0.5 6.72 Example 83 5 Preparation 87.28 Copolymer II 1.0 6.72 Example 84 5 Preparation 82.28 Copolymer II 1.0 6.72 Example 85 10 Preparation 80.28 Copolymer II 3.0 6.72 Example 86 10 Preparation 70.28 Copolymer II 3.0 6.72 Example 87 20 Preparation 62.78 Copolymer II 0.5 6.72 Example 88 30 Preparation 62.28 Copolymer II 1.0 6.72 Example 89 30 Preparation 60.28 Copolymer II 3.0 6.72 Example 90 30 Preparation 58.28 Copolymer II 5.0 6.72 Example 91 30 Preparation 93.13 Copolymer III 0.1 6.72 Example 91 0.05 Preparation 92.73 Copolymer III 0.5 6.72 Example 93 0.05 Preparation 92.23 Copolymer III 1.0 6.72 Example 94 0.05 Preparation 90.23 Copolymer III 3.0 6.72 Example 95 0.05 Preparation 87.78 Copolymer III 0.5 6.72 Example 96 5 Preparation 83.28 Copolymer III 5.0 6.72 Example 97 5 Preparation 82.78 Copolymer III 0.5 6.72 Example 98 10 Preparation 78.28 Copolymer III 5.0 6.72 Example 99 10 Preparation 72.78 Copolymer III 0.5 6.72 Example 100 20 Preparation 72.28 Copolymer III 1.0 6.72 Example 101 20 Preparation 68.28 Copolymer III 5.0 6.72 Example 102 20 Preparation 58.28 Copolymer III 5.0 6.72 Example 103 30 Preparation 58.18 Copolymer III 0.1 6.72 Example 104 35 Preparation 57.78 Copolymer III 0.5 6.72 Example 105 35 Preparation 57.28 Copolymer III 1.0 6.72 Example 106 35 Preparation 55.28 Copolymer III 3.0 6.72 Example 107 35 Preparation 93.13 Copolymer IV 0.1 6.72 Example 108 0.05 Preparation 92.73 Copolymer IV 0.5 6.72 Example 109 0.05 Preparation 92.23 Copolymer IV 1.0 6.72 Example 110 0.05 Preparation 90.23 Copolymer IV 3.0 6.72 Example 111 0.05 Preparation 88.23 Copolymer IV 5.0 6.72 Example 112 0.05 Preparation 88.18 Copolymer IV 0.1 6.72 Example 113 5 Preparation 85.28 Copolymer IV 3.0 6.72 Example 114 5 Preparation 83.28 Copolymer IV 5.0 6.72 Example 115 5 Preparation 78.28 Copolymer IV 10.0 6.72 Example 116 5 Preparation 83.18 Copolymer IV 0.1 6.72 Example 117 10 Preparation 82.78 Copolymer IV 0.5 6.72 Example 118 10 Preparation 78.28 Copolymer IV 5.0 6.72 Example 119 10 Preparation 73.18 Copolymer IV 0.1 6.72 Example 120 20 Preparation 72.78 Copolymer IV 0.5 6.72 Example 121 20 Preparation 70.28 Copolymer IV 3.0 6.72 Example 122 20 Preparation 93.13 Copolymer V 0.1 6.72 Example 123 0.05 Preparation 92.73 Copolymer V 0.5 6.72 Example 124 0.05 Preparation 92.23 Copolymer V 1.0 6.72 Example 125 0.05 Preparation 90.23 Copolymer V 3.0 6.72 Example 126 0.05 Preparation 88.23 Copolymer V 5.0 6.72 Example 127 0.05 Preparation 88.18 Copolymer V 5 0.1 6.72 Example 128 Preparation 87.78 Copolymer V 5 0.5 6.72 Example 129 Preparation 83.28 Copolymer V 5 5.0 6.72 Example 130 Preparation 82.78 Copolymer V 0.5 6.72 Example 131 10 Preparation 78.28 Copolymer V 5.0 6.72 Example 132 10 Preparation 72.78 Copolymer V 0.5 6.72 Example 133 20 Preparation 72.28 Copolymer V 1.0 6.72 Example 134 20 Preparation 63.18 Copolymer V 0.1 6.72 Example 135 30 Preparation 90.23 Copolymer VI 3.0 6.72 Example 136 0.05 Preparation 88.23 Copolymer VI 5.0 6.72 Example 137 0.05 Preparation 87.78 Copolymer VI 0.5 6.72 Example 138 5 Preparation 85.28 Copolymer VI 3.0 6.72 Example 139 5 Preparation 83.18 Copolymer VI 0.1 6.72 Example 140 10 Preparation 82.28 Copolymer VI 1.0 6.72 Example 141 10 Preparation 78.28 Copolymer VI 5.0 6.72 Example 142 10 Preparation 70.28 Copolymer VI 3.0 6.72 Example 143 20 Preparation 58.18 Copolymer VI 0.1 6.72 Example 144 35 Preparation 57.78 Copolymer VI 0.5 6.72 Example 145 35 Preparation 57.28 Copolymer VI 1.0 6.72 Example 146 35 Preparation 55.28 Copolymer VI 3.0 6.72 Example 147 35 Preparation 53.28 Copolymer VI 5.0 6.72 Example 148 35 Comparative 93.23 Copolymer IV — 6.72 Example 10 0.05 Comparative 88.28 Copolymer IV — 6.72 Example 11 5 Comparative 83.28 Copolymer IV — 6.72 Example 12 10 Comparative 88.28 Copolymer V 5 — 6.72 Example 13 Comparative 73.28 Copolymer V — 6.72 Example 14 20 Comparative 63.28 Copolymer V — Example 15 30 6.72 Comparative 88.28 Copolymer VI — Example 16 5 6.72

4. Evaluation of Properties

The properties of the lubricant compositions prepared in Preparation Examples and Comparative Examples were measured as follows. The results are shown in Tables 6 and 7 below.

Friction Coefficient

In the ball-on-disc mode, friction performance was evaluated by sequentially elevating the temperature in increments of 10□ from 40 to 120□ at 50 Hz and comparing the average friction coefficients at individual temperatures. Here, the friction coefficient value decreases with an increase in effectiveness.

Traction Coefficient

The traction coefficient was measured using an MTM instrument made by PCS Instruments. Here, the measurement conditions were fixed at 50N and SRR 50%, and friction and traction were observed depending on changes in temperature. The temperature was varied from 40 to 120□, and the average values were compared.

Wear Resistance

Four steel balls were subjected to friction with the lubricant composition for 60 min under conditions of 20 kg load, 1200 rpm, and 54□, the sizes of wear scars were compared, and evaluation was carried out in accordance with ASTM D4172. Here, the wear scar (average wear scar diameter, μm) value decreases with an increase in effectiveness.

Oxidation Stability

Oxidation stability was measured using an RBOT (Rotational Bomb Oxidation Test) meter in accordance with ASTM D2271.

Friction Loss

As a gear oil rig test, an FZG gear efficiency test was performed. In the FZG efficiency test, the pinion torque was measured through rotation with a motor drive specified depending on the type of oil under conditions in which the temperature of oil was fixed to 100° C. and no load was applied, and thus the pinion torque loss rates of existing oil and the oil using the alphaolefin copolymer and the alkylated phosphonium compound were calculated, and relative values thereof were compared.

TABLE 6 Relative 4 loss SRV MTM Ball (FZG Friction Traction Wear Oxidation efficiency Coefficient Coefficient (μm) stability at 100° C.) Preparation 0.701 0.598 496 610 1.20 Example 1 Preparation 0.732 0.569 477 654 1.09 Example 2 Preparation 0.734 0.587 432 523 1.16 Example 3 Preparation 0.735 0.544 501 320 1.30 Example 4 Preparation 0.712 0.523 665 249 1.30 Example 5 Preparation 0.285 0.200 152 1650 0.91 Example 6 Preparation 0.265 0.236 133 1600 0.90 Example 7 Preparation 0.267 0.211 110 2000 0.95 Example 8 Preparation 0.240 0.236 106 2110 0.94 Example 9 Preparation 0.736 0.569 511 333 1.15 Example 10 Preparation 0.239 0.207 123 1840 0.91 Example 11 Preparation 0.257 0.217 140 1680 0.92 Example 12 Preparation 0.745 0.564 522 285 1.22 Example 13 Preparation 0.259 0.243 147 1510 0.93 Example 14 Preparation 0.754 0.555 536 278 1.20 Example 15 Preparation 0.710 0.621 588 299 1.18 Example 16 Preparation 0.768 0.561 555 269 1.18 Example 17 Preparation 0.769 0.532 622 298 1.16 Example 18 Preparation 0.774 0.512 654 277 1.09 Example 19 Preparation 0.744 0.533 635 279 1.16 Example 20 Preparation 0.730 0.612 598 311 1.14 Example 21 Preparation 0.741 0.633 590 312 1.16 Example 22 Preparation 0.76 0.685 518 384 1.20 Example 23 Preparation 0.769 0.696 523 368 1.18 Example 24 Preparation 0.778 0.641 537 321 1.14 Example 25 Preparation 0.792 0.621 556 325 1.16 Example 26 Preparation 0.791 0.632 631 387 1.12 Example 27 Preparation 0.278 0.236 107 1610 0.93 Example 28 Preparation 0.279 0.245 108 1440 0.91 Example 29 Preparation 0.284 0.278 121 2130 0.92 Example 30 Preparation 0.291 0.247 122 2410 0.93 Example 31 Preparation 0.793 0.612 623 345 1.19 Example 32 Preparation 0.777 0.548 505 269 1.16 Example 33 Preparation 0.269 0.219 158 1780 0.95 Example 34 Preparation 0.264 0.209 169 1790 0.93 Example 35 Preparation 0.797 0.587 647 388 1.20 Example 36 Preparation 0.81 0.521 644 415 1.14 Example 37 Preparation 0.258 0.221 152 1540 0.92 Example 38 Preparation 0.755 0.555 612 321 1.30 Example 39 Preparation 0.841 0.623 698 610 1.15 Example 40 Preparation 0.702 0.665 678 654 1.14 Example 41 Preparation 0.682 0.610 598 523 1.16 Example 42 Preparation 0.713 0.587 599 320 1.30 Example 43 Preparation 0.715 0.588 587 333 1.15 Example 44 Preparation 0.258 0.211 175 2020 0.95 Example 45 Preparation 0.716 0.521 499 285 1.22 Example 46 Preparation 0.269 0.207 154 1650 0.92 Example 47 Preparation 0.717 0.569 580 278 1.20 Example 48 Preparation 0.278 0.217 135 1580 0.92 Example 49 Preparation 0.279 0.213 108 1490 0.93 Example 50 Preparation 0.726 0.587 590 269 1.18 Example 51 Preparation 0.693 0.587 520 495 1.15 Example 52 Preparation 0.231 0.247 163 2456 0.94 Example 53 Preparation 0.691 0.587 651 419 1.14 Example 54 Preparation 0.711 0.547 587 322 1.12 Example 55 Preparation 0.268 0.236 199 1680 0.91 Example 56 Preparation 0.264 0.248 185 2020 0.92 Example 57 Preparation 0.247 0.278 169 2122 0.93 Example 58 Preparation 0.254 0.219 165 1681 0.93 Example 59 Preparation 0.260 0.217 155 1519 0.92 Example 60 Preparation 0.678 0.512 655 279 1.16 Example 61 Preparation 0.621 0.547 591 325 1.18 Example 62 Preparation 0.278 0.243 123 1440 0.93 Example 63 Preparation 0.744 0.587 478 347 1.16 Example 64 Preparation 0.685 0.611 664 269 1.18 Example 65 Preparation 0.655 0.587 673 396 1.16 Example 66 Preparation 0.745 0.587 599 348 1.16 Example 67 Preparation 0.725 0.555 568 384 1.30 Example 68 Preparation 0.756 0.548 534 368 1.15 Example 69 Preparation 0.291 0.245 149 1810 0.91 Example 70 Preparation 0.269 0.278 107 1790 0.92 Example 71 Preparation 0.284 0.256 110 1540 0.94 Example 72 Comparative 0.721 0.589 454 510 1.11 Example 1 Comparative 0.759 0.674 505 348 1.22 Example 2 Comparative 0.775 0.555 436 258 1.30 Example 3 Comparative 0.811 0.588 698 412 1.18 Example 4 Comparative 0.766 0.672 664 510 1.16 Example 5 Comparative 0.725 0.611 510 465 1.30 Example 6 Comparative 0.68 0.563 636 249 1.30 Example 7 Comparative 0.7 0.587 597 321 1.20 Example 8 Comparative 0.716 0.539 498 396 1.30 Example 9

TABLE 7 Relative 4 loss SRV MTM Ball (FZG Friction Traction Wear Oxidation efficiency Coefficient Coefficient (μm) stability at 100□) Preparation 0.268 0.209 122 1640 0.93 Example 73 Preparation 0.269 0.236 132 1490 0.91 Example 74 Preparation 0.247 0.200 164 2110 0.92 Example 75 Preparation 0.231 0.236 176 2030 0.93 Example 76 Preparation 0.254 0.211 161 1580 0.95 Example 77 Preparation 0.251 0.236 196 1490 0.94 Example 78 Preparation 0.269 0.207 193 1480 0.91 Example 79 Preparation 0.278 0.222 190 1650 0.92 Example 80 Preparation 0.277 0.236 167 1480 0.93 Example 81 Preparation 0.284 0.245 189 2020 0.94 Example 82 Preparation 0.268 0.278 107 2456 0.93 Example 83 Preparation 0.269 0.247 108 1854 0.91 Example 84 Preparation 0.284 0.219 121 1440 0.92 Example 85 Preparation 0.291 0.209 122 2080 0.93 Example 86 Preparation 0.264 0.200 169 1810 0.93 Example 87 Preparation 0.749 0.555 520 298 1.12 Example 88 Preparation 0.748 0.569 555 277 1.19 Example 89 Preparation 0.75 0.539 562 279 1.16 Example 90 Preparation 0.755 0.587 458 249 1.30 Example 91 Preparation 0.798 0.639 655 346 1.16 Example 91 Preparation 0.768 0.589 636 347 1.30 Example 93 Preparation 0.736 0.598 664 258 1.15 Example 94 Preparation 0.747 0.569 673 269 1.22 Example 95 Preparation 0.254 0.236 194 1540 0.93 Example 96 Preparation 0.822 0.587 676 287 1.20 Example 97 Preparation 0.260 0.207 123 1640 0.95 Example 98 Preparation 0.813 0.544 618 288 1.18 Example 99 Preparation 0.269 0.222 140 1490 0.93 Example 100 Preparation 0.278 0.219 146 2020 0.91 Example 101 Preparation 0.702 0.569 589 299 1.14 Example 102 Preparation 0.682 0.564 597 388 1.12 Example 103 Preparation 0.726 0.512 478 347 1.22 Example 104 Preparation 0.735 0.533 436 321 1.20 Example 105 Preparation 0.749 0.523 505 247 1.18 Example 106 Preparation 0.748 0.532 518 258 1.14 Example 107 Preparation 0.693 0.548 587 322 1.30 Example 108 Preparation 0.704 0.512 541 368 1.15 Example 109 Preparation 0.779 0.563 523 388 1.22 Example 110 Preparation 0.77 0.611 498 396 1.20 Example 111 Preparation 0.691 0.587 599 348 1.18 Example 112 Preparation 0.722 0.521 534 368 1.12 Example 113 Preparation 0.284 0.209 198 1650 0.92 Example 114 Preparation 0.715 0.555 612 345 1.15 Example 115 Preparation 0.716 0.672 647 346 1.13 Example 116 Preparation 0.726 0.498 644 258 1.30 Example 117 Preparation 0.291 0.278 107 1580 0.94 Example 118 Preparation 0.745 0.623 612 299 1.18 Example 119 Preparation 0.725 0.665 664 388 1.14 Example 120 Preparation 0.264 0.219 121 1480 0.91 Example 121 Preparation 0.269 0.256 110 1910 0.93 Example 122 Preparation 0.758 0.600 678 415 1.19 Example 123 Preparation 0.759 0.588 598 369 1.16 Example 124 Preparation 0.76 0.541 599 358 1.30 Example 125 Preparation 0.769 0.563 587 347 1.16 Example 126 Preparation 0.778 0.522 499 321 1.30 Example 127 Preparation 0.716 0.563 789 317 1.20 Example 128 Preparation 0.268 0.221 158 1480 0.93 Example 129 Preparation 0.713 0.532 580 365 1.15 Example 130 Preparation 0.264 0.236 174 2122 0.95 Example 131 Preparation 0.645 0.555 589 285 1.22 Example 132 Preparation 0.247 0.219 152 2456 0.93 Example 133 Preparation 0.231 0.211 169 1854 0.91 Example 134 Preparation 0.735 0.547 510 250 1.14 Example 135 Preparation 0.758 0.512 578 321 1.22 Example 136 Preparation 0.759 0.563 579 325 1.20 Example 137 Preparation 0.251 0.207 154 2080 0.93 Example 138 Preparation 0.260 0.234 169 2130 0.94 Example 139 Preparation 0.798 0.578 485 287 1.22 Example 140 Preparation 0.259 0.209 220 1810 0.93 Example 141 Preparation 0.822 0.601 444 412 1.12 Example 142 Preparation 0.261 0.226 226 1780 0.91 Example 143 Preparation 0.769 0.587 584 345 1.14 Example 144 Preparation 0.778 0.588 562 346 1.12 Example 145 Preparation 0.792 0.541 532 347 1.19 Example 146 Preparation 0.791 0.513 521 258 1.16 Example 147 Preparation 0.793 0.555 511 269 1.30 Example 148 Comparative 0.725 0.555 651 269 1.16 Example 10 Comparative 0.711 0.588 568 384 1.14 Example 11 Comparative 0.717 0.499 698 347 1.16 Example 12 Comparative 0.715 0.543 590 399 1.22 Example 13 Comparative 0.749 0.555 587 321 1.19 Example 14 Comparative 0.646 0.569 523 278 1.20 Example 15 Comparative 0.76 0.611 624 387 1.18 Example 16

As is apparent from Tables 6 and 7, the lubricant compositions including the liquid olefin copolymer and the alkylated phosphonium compound within the amount ranges of the present invention were significantly reduced in wear scar and friction coefficient compared to the lubricant compositions of Comparative Examples, and also exhibited superior oxidation stability.

Moreover, an efficiency improvement of at least 5 to 12% in the FZG gear efficiency test resulted, indicating that, even in practical use, the lubricant composition of the present invention was capable of reducing gear loss, thereby significantly improving fuel economy or energy-saving effects.

Therefore, it is concluded that the lubricant composition of the present invention is improved from the aspects of friction characteristics and stability and thus is suitable for use in gear oil.

Although the embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A lubricant composition, comprising: 70.28 to 95.79% by weight of a base oil, 0.5 to 20% by weight of a liquid olefin copolymer, and 0.5 to 3.0% by weight of an alkylated phosphonium compound, wherein the base oil is at least one selected from the group consisting of mineral oil, polyalphaolefin (PAO), and ester, the liquid olefin copolymer has a coefficient of thermal expansion of 3.0 to 3.8, and the alkylated phosphonium compound is at least one selected from the group consisting of tetraoctylated phosphonium bis-ethylhexyl phosphate, tributyltetradecylphosphonium bis(2-ethylhexyl)phosphate, tetraethylphosphonium bis(2-ethylhexyl)phosphate, and tributylphosphonium bis(2-ethylhexly)phosphate, and wherein the lubricant composition has a SRV friction coefficient of 0.231 to 0.291.
 2. The lubricant composition of claim 1, wherein the liquid olefin copolymer is prepared by copolymerizing ethylene and alphaolefin using a single-site catalyst system.
 3. The lubricant composition of claim 2, wherein the single-site catalyst system includes a metallocene catalyst, an organometallic compound and an ionic compound.
 4. The lubricant composition of claim 1, wherein the liquid olefin copolymer has a bromine number of 0.1 or less.
 5. The lubricant composition of claim 1, further comprising an additive selected from the group consisting of an antioxidant, a metal cleaner, an anticorrosive agent, a foam inhibitor, a pour-point depressant, a viscosity modifier, a wear-resistant agent, and combinations thereof.
 6. The lubricant composition of claim 1, wherein the lubricant composition has a traction coefficient of 0.15 to 0.3.
 7. The lubricant composition of claim 1, wherein the lubricant composition has a pinion torque loss rate due to friction of less than 1% in an FZG gear efficiency test.
 8. The lubricant composition of claim 1, wherein the lubricant composition is used as gear oil. 